Synthesis and Characterization of Triangular-pyramidal Bismuth Oxide via a One-step Chemical Precipitation Route

Triangular-pyramidal ω-Bi2O3 is successfully synthesized via a one-step wet-chemical method.XRD,SEM,and UV-vis have been employed to characterize the as-prepared samples.Structural characterization by XRD confirms the formation of triclinic ω-Bi2O3 with high purity.The well-defined flowerlike Bi2O3 structures consisted of many triangular-pyramids are formed.Preparative parameters,such as concentration of PEG 6000,have great effects on the morphology and the particle size.The obvious absorption edge for ω-Bi2O3 powder is located at about 493 nm,which corresponds to the optical band gap energy of2.73 eV.

Synthesis of condensed polynuclear aromatic resin from furfural extract oil of reduced-pressure route Ⅱ

As an industrial byproduct of oil refining,furfural extract oil from reduced-pressure route Ⅱ with high aromatic content was used to prepare heat-resistant condensed polynuclear aromatic（COPNA） resin for the first time.The basic properties of furfural extract oil and the resultant COPNA resin were characterized by infrared spectroscopy（FT-IR）,nuclear magnetic resonance spectroscopy（1H-NMR）,thermogravimetric analysis（TGA） and elemental analysis（EA）.The result showed that heat treated furfural extract oil was successfully used for the synthesis of heat-resistant COPNA resin.The average structural parameters of raw materials and prepared resin were calculated by the improved Brown-Ladner method,and the averaged molecular structure of the resin was obtained.The reaction mechanism for the synthesis of COPNA resin was suggested as an acid-catalyzed positive ion type polymerization.

A New Route for Synthesis of Entecavir

A new economical synthetic route of the key intermediate 6. The synthesis of a modified Mitsunobu reaction. of entecavir was presented, involving the preparation 6 was conveniendy achieved in good overall yield by a modified Mitsunobu reaction.

Superconducting Single-Layer T-Graphene and Novel Synthesis Routes

Single-layer superconductors are ideal materials for fabricating superconducting nano devices.However,up to date,very few single-layer elemental superconductors have been predicted and especially no one has been successfully synthesized yet.Here,using crystal structure search techniques and ab initio calculations,we predict that a single-layer planar carbon sheet with 4-and 8-membered rings called T-graphene is a new intrinsic elemental superconductor with superconducting critical temperature(Tc)up to around 20.8 K.More importantly,we propose a synthesis route to obtain such a single-layer T-graphene,that is,a T-graphene potassium intercalation compound(C4 K with P4/mmm symmetry)is firstly synthesized at high pressure(>11.5 GPa)and then quenched to ambient condition;and finally,the single-layer T-graphene can be either exfoliated using the electrochemical method from the bulk C4 K,or peeled off from bulk T-graphite C4,where C4 can be obtained from C4 K by evaporating the K atoms.Interestingly,we find that the calculated Tc of C4 K is about 30.4 K at 0 GPa,which sets a new record for layered carbon-based superconductors.The present findings add a new class of carbon-based superconductors.In particular,once the single-layer T-graphene is synthesized,it can pave the way for fabricating superconducting devices together with other 2 D materials using the layer-by-layer growth techniques.

Effect of the synthesis route on the structural and dielectric properties of SrBi1.8Y0.2Nb2O9 ceramics

This work is devoted to the synthesis and characterization of yttrium-doped SrBi_2Nb_2O_9 ceramics prepared by three methods: solid state reaction, co-precipitation, and hydrothermal. Multiple characterizations, specifically scanning electron microscopy(SEM), X-ray powder diffraction(XRD), and Fourier transform infrared spectroscopy(FTIR), were used to validate the structural feature. The crystallite size was estimated by Scherrer's formula and the Williamson–Hall plot. The effect of the process on the band intensities of the FTIR spectra was investigated. The crystallite size and microstructure of ceramics prepared from different synthesis processes were strongly influenced by the sinterability. SEM images revealed nanograin ceramics for materials prepared by co-precipitation and hydrothermal methods and micrograin ceramics prepared by the solid state method. The synthesized compounds underwent phase transitions at 480–465°C. The dielectric and electrical properties of these Y-doped SrBi_2Nb_2O_9 ceramics appear to be dependent on the grain size.

One-step synthesis of Pt@ZIF-8 catalyst for the selective hydrogenation of 1,4-butynediol to 1,4-butenediol

A catalyst consisting of platinum nanoparticles on a ZIF-8 support（Pt@ZIF-8） was synthesized in a straightforward one-step procedure,by adding a nanostructured platinum sol during the formation of ZIF-8 at room temperature.Pt@ZIF-8 was highly porous and well crystallized.The Pt nanoparticles were well dispersed within the ZIF-8 support.In the hydrogenation of 1,4-butynediol,Pt@ZIF-8 exhibited high activity,excellent selectivity for 1,4-butenediol of greater than 94%,and reusability.The Pt@ZIF-8 catalyst did not require further additives.The favorable catalytic performance was attributed primarily to the modification of the ZIF-8 support by the platinum nanoparticles.

Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

Biomass has become of recent interest as a raw material for‘green’graphenic carbon(GC)since it promotes an environmentally friendly approach.Here,we investigate a single pyrolysis route to synthesize GC from coconut shells which provides a simple method and can produce a high yield,thus being convenient for large-scale pro-duction.The pyrolysis involves a stepped holding process at 350℃ for 1 h and at 650℃ or 900℃ for 3 h.The GC sample resulted at the 900℃ pyrolysis has a thinner sheet,a less porous structure,a higher C/O ratio,and an enhanced electrical conductivity than those pyrolyzed at 650℃.The addition of Na3PO4 catalyst has no signifi-cant effects on the GC structures obtained by this route.The single pyrolysis route generates thinner GC sheets compared to the two-step heat treatment followed by the liquid phase exfoliation(LPE)procedure.Nevertheless,the latter method offers a formation of clean samples with a porous or holey feature which has potential for advanced energy-storage applications.

Fabrication of Al_2O_3-NaCl Composite Heat Storage Materials by One-step Synthesis Method

Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al2O3composite materials were synthesized by one-step synthesis method. The chemical composition, morphology, structure, and thermal properties were investigated by XRD, EDS, SEM, and DSC. The results show that NaCl can be absorbed by Al2O3particle from 800 to 900 ℃ for Al2O3particle surface is rich active structure. The results also indicate that the leakage of NaCl when the phase change can be prevented by Al2O3particles and the enthalpy of phase change of NaCl-Al2O3material is 362 J/g. The composites have an excellent heat storage capacity. Therefore, this study contributes to one new thought and method to prepare high temperature heat storage material and this material can be applied in future thermal engineering.

Catalytic kinetics of dimethyl ether one-step synthesis over CeO_2–CaO–Pd/HZSM-5 catalyst in sulfur-containing syngas process

CeO_2–CaO–Pd/HZSM-5 catalyst was prepared for the dimethyl ether(DME) one-step synthesis in a continuous fixed-bed micro-reactor from the sulfur-containing syngas. The catalytic stability over hybrid catalyst of CeO_2–CaO–Pd/HZSM-5 was investigated to ensure that the kinetics experimental results were not significantly influenced by induction period and catalytic deactivation. A large number of kinetic data points(40 sets) were obtained over a range of temperature(240–300 °C), pressure(3–4 MPa), gas hourly space velocity(GHSV)(2000–3000 L·kg^(-1)·h^(-1)) and H_2/CO mole ratio(2–3). Kinetic model for the methanol synthesis reaction and the dehydration of methanol were obtained separately according to reaction mechanism and Langmuir–Hinshelwood mechanism. Regression parameters were investigated by the method combining the simplex method and Runge–Kutta method. The model calculations were in appropriate accordance with the experimental data.

A LOW-PRESSURE AND ONE-STEP METHOD FOR THE SYNTHESIS OF ALKYLIDYNETRICOBALT NONACARBONYL CLUSTERS:RCCo_8(CO)_9

Metal clusters RCCo_3(CO)_9(R-H,C1,Br,CH_3,Ph) were prepared in 18.8-57.3% yields from the reaction of cobalt(Ⅱ)salt and RCX_a under mild PTC conditions(latm CO,25℃).The cobalt salt was reduced to Co(CO)_4 in the presence of Na_3S_2O_4.

Effects of doping route on microstructure and mechanical properties of W−1.0wt.%La2O3 alloys

A comparative study was conducted by using solution combustion synthesis with three different doping routes(liquid-liquid(WL10), liquid-solid(WLNO) and solid-solid(WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W-1.0 wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W-1.0 wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples;the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 ℃ with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of(57±29.7) and(27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W-1.0 wt.%La2O3 alloy via the liquid-liquid doping route, as compared with conventionally-manufactured tungsten materials.

Synthesis of Methyl Isopropyl Ketone and Diethyl Ketone over Ni-Na/ZrO_2-MnO_2-ZnO Catalyst

ZrO2-MnO2-ZnO supports were prepared by the co-precipitation method,and then Ni-Na/ZrO2-MnO2-ZnO catalysts were prepared by the impregnation method.In this paper,the reactions to synthesize methyl isopropyl ketone and diethyl ketone by the one-step synthesis method over this catalyst were studied,and meanwhile,the impact of the catalyst preparation conditions and the reaction conditions on catalyst performance was also investigated.It was observed that under the conditions when Ni loading was 25%,calcination temperature was 400℃ and reduction temperature was 410℃,this catalyst had good catalytic performance on the reaction.The suitable reaction conditions were achieved:reaction temperature was 400℃;reaction at atmospheric pressure;liquid hourly space velocity of raw material of 0.5 h 1 ;and the molar ratio of(methanol)/(methyl ethyl ketone)/(water) was equal to 1/1/1.Under such conditions,the conversion of methyl ethyl ketone could achieve 41.7%,and the overall selectivity of methyl isopropyl ketone and diethyl ketone could achieve 83.3%,which was comparable to the conversion of 38.1% and the selectivity of 82.2% achieved by using palladium as the active material.The good stability made this catalyst have good prospects for industrial application.

Synthesis of Codon-optimized Human Interleukin-18 Gene by Combination of Chemical and Enzymatic Method

According to the amino acid sequence and codon preference of E. coli, the human interleukin-18（IL-18） gene was optimized to avoid the rare codons. The total length of the synthesized gene is 571 bp; 18 oligonucleotides, DNA fragments were designed and synthesized by the phosphoramidite four-step chemical method. The whole DNA sequence was synthesized by a one-step total gene synthesis method, and then inserted in pUC18 vector. Five positive clones identified by blue-white colony screening were sent to Shanghai Sangon Biological Engineering Technology and Service Co., Ltd. for sequencing. The sequencing result shows that one clone contained the complete correct gene in all the five positive clones.

Highly efficient subnanometer Ru-based catalyst for ammonia synthesis via an associative mechanism

The industrial manufacture of ammonia(NH_(3))using Fe-based catalyst works under rigorous conditions.For the goal of carbon-neutrality,it is highly desired to develop advanced catalyst for NH_(3)synthesis at mild conditions to reduce energy consumption and CO_(2)emissions.However,the main challenge of NH_(3)synthesis at mild conditions lies in the dissociation of steady N≡N triple bond.In this work,we report the design of subnanometer Ru clusters(0.8 nm)anchored on the hollow N-doped carbon spheres catalyst(Ru-SNCs),which effectively promotes the NH_(3)synthesis at mild conditions via an associative route.The NH_(3)synthesis rate over Ru-SNCs(0.49%(mass)Ru)reaches up to 11.7 mmol NH_(3)·(g cat)^(-1)·h^(-1) at 400℃ and 3 MPa,which is superior to that of 8.3 mmol NH_(3)·(g cat)^(-1)·h^(-1) over Ru nanoparticle catalyst(1.20%(mass)Ru).Various characterizations show that the N_(2)H_(4)species are the main intermediates for NH_(3)synthesis on Ru-SNCs catalyst.It demonstrates that Ru-SNCs catalyst can follow an associative route for N_(2)activation,which circumvents the direct dissociation of N_(2)and results in highly efficient NH_(3)synthesis at mild conditions.

Controllable synthesis of novel nanoporous manganese oxide catalysts for the direct synthesis of imines from alcohols and amines

A novel template-free oxalate route was applied to synthesize different mesoporous manganese oxides(amorphous manganese oxide(AMO),Mn5 O8,Mn3 O4,Mn O2)in the narrow temperature range from 350°C to 400°C by controlling the calcination conditions,which were employed as the efficient catalysts for the oxidative coupling of alcohols with amines to imines.The chemical and structural properties of the manganese oxides were characterized by the methods of thermogravimetry analysis and heat flow(TG-DSC),X-ray diffraction(XRD),nitrogen sorption,scanning electron microscope(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),H2 temperature-programmed reduction(H2-TPR),and inductively coupled plasma optical emission spectrometry(ICP-OES)techniques.The structures of different manganese oxides were confirmed by characterization.The M-350(AMO)presented the maximum surface area,amorphous nature,the lowest reduction temperature,the higher(Mn3++Mn4+)/Mn2+ratio,and the higher adsorbed oxygen species compared to other samples.Among the catalysts,M-350 showed the best catalytic performance using air as an oxidant,and the conversion of benzyl alcohol(BA)and the selectivity of N-benzylideneaniline(NBA)reached as high as 100%and 97.1%respectively at the lower reaction temperature(80°C)for 1 h.M-350 had also the highest TOF value(0.0100 mmol·mg-1·h-1)compared to the other manganese oxide catalysts.The catalyst was reusable and gave 95.8%conversion after 5 reuse tests,the XRD pattern of the reactivated M-350 did not show any obvious change.Lattice oxygen mobility and(Mn3++Mn4+)/Mn2+ratio were found to play the important roles in the catalytic activity of aerobic reactions.

Chemical Synthesis of C3N and BC2N Compounds

A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of 400℃. Measurements of FTIR, XRD, TEM and EELS show that two kinds of compounds have been formed in the prepared sample. One is hollow sphere-like C-N with an amorphous, structure; the other is piece-like polycrystalline B-C-N with the hexagonal structure. Their determined compositions are close to C3N and BC2N, respectively.

Multi-step Reaction Route Developed for Improving Crystallinity of Boron Nitride Nanoparticles

A multi-step reaction route was developed to synthesize boron nitride（BN） nanoparticles via the reactionbetween NaN3 and BC13 in a benzene-thermal solution. By means of this route, the crystallinity of BN nanoparticleswas improved via increasing the reaction steps. Meanwhile, a phase transformation from hexagonal BN（hBN） or tur-bostratic BN（tBN） to cubic BN（cBN） occurred, resulting in the increase of cBN content. Moreover, the content ofcBN also slightly increased when the temperature was elevated from 265 ℃ to 280 ℃.

Novel Synthesis, Crystal Structure, and Plant-growth Regulation Activity of(1S,4R)-4,7,7-Trimethyl-6-oxabicyclo[3.2.1]octane-1,4-diol

The title compound,（1S,4R）-4,7,7-trimethyl-6-oxabicyclo [3.2.1] octane-1,4-diol（C（10）H（18）O3）, has been synthesized from terpinolene via one-step catalytic synthetic method and structurally characterized by means of HRMS, IR, 1H-NMR, （13）C-NMR and single-crystal X-ray diffraction. The compound crystallizes in trigonal, space group R-3, with a = 27.892（9）, b = 27.892（9）, c = 6.720（2） A, γ = 120°, Z = 18, V = 4527（3） A3, Dc = 1.230 g/cm3, Mr = 186.24, λ（Mo Kα） = 0.71073？, μ = 0.09 mm（-1）, F（000） = 1836, the final R = 0.051 and wR = 0.161. The title compound molecule contained a 6-oxabicyclo[3.2.1]octane skeleton and two hydroxyl groups, which were connected through intermolecular O–H…O hydrogen bonds to generate a two-dimensional network. Especially, the preliminary bioassay showed that the title compound can promote the root growth and shoot elongation of rape（Brassica campestris） at low concentration（0.62570 mmol·L^-1） and inhibit them at high concentration（〉 70 mmol·L^-1）.

Selective Synthesis of Different-Sized Gold Nanoclusters through HCI-Etching and-Growth Effect

Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 and Au13 clusters through adding HCl to the traditional Aull synthetic route at different reaction time. Time-dependent mass spectra and UV- Vis spectra were ernployed to monitor these two HCl-directed processes, and revealed the distinct roles of HCl as an etchant or a growth prornotor, respectively. Furthermore, parallel experiments on independent synthetic routes involving only non-chlorine H＋ （acetic acid） or Cl （tetraethy larnrnoniurn chloride） instead of HCl were perforrned, which illustrated the main role of H^＋-etching and Cl^ -assisted growth in HCl-directed cluster synthetic routes. We propose the HCl-etching is mainly achieved via the H＋ action to break the Au（I）-PPh3 part of clusters, while the HCl-prornoted growth is realized via the attachment of Au-Cl species to the pre-forrned clusters.